For purposes of assembly, the cylinder bore portion and cylinder head of a compressor cylinder normally comprises two parts. The lower portion of the cylinder head is designed as a valve plate for accommodating the intake and pressure discharge valves, with an intake valve spring disposed adjacent the lower side of the intake valve for biasing it toward a closed position. Since the valve plate also limits the compression space or chamber, the juncture between the head and bore portion must be hermetically sealed; this is only assured by extremely precise machining of the edges and by a seal. Compressors in which the valve plate comprises a separate component are also known.
The designs described above, therefore, comprise a large number of individual parts that are expensive to produce. It is conceivable that the number of necessary individual parts could be reduced by combining individual parts in one or a few castings.
However, it has been found that, when several individual parts are simply combined in a single casting, considerable problems are encountered in the mounting of the valve.